Add trips page

Creating a new entity called a trip. This will group together any travel
accommodation and conferences that happen together on one trip.

A trip is assumed to start when leaving home and finish when returning
home.

The start date of a trip in is the trip ID. The date is written in ISO
format.

This assumes there cannot be multiple trips one one day. This assumption
might be wrong, for example a morning day trip by rail, then another
trip starts in the afternoon. I can change my choice of using dates as
trip IDs if that happens.

Sometimes during the planning of a trip the start date is unknown. For
now we make up a start date, we can always change it later. If we use
the start date in URLs then the URLs will change. Might need to keep a
file of redirects, or could think of a different style of identifier.

Trip ID have been added to accommodation, conferences, trains and
flights.

Later there will be a trips.yaml with notes about each trip.

templates/macros.html

@@ -0,0 +1,96 @@
+{% macro display_datetime(dt) %}{{ dt.strftime("%a, %d, %b %Y %H:%M %z") }}{% endmacro %}
+{% macro display_time(dt) %}{{ dt.strftime("%H:%M %z") }}{% endmacro %}
+
+{% macro conference_row(item, badge) %}
+  {% set country = get_country(item.country) if item.country else None %}
+  <div class="grid-item text-end">{{ item.start.strftime("%a, %d %b %Y") }}</div>
+  <div class="grid-item text-end">{{ item.end.strftime("%a, %d %b") }}</div>
+  <div class="grid-item">
+    {% if item.url %}
+      <a href="{{ item.url }}">{{ item.name }}</a>
+    {% else %}
+      {{ item.name }}
+    {% endif %}
+    {% if item.going and not (item.accommodation_booked or item.travel_booked) %}
+      <span class="badge text-bg-primary">
+        {{ badge }}
+      </span>
+    {% endif %}
+    {% if item.accommodation_booked %}
+      <span class="badge text-bg-success">accommodation</span>
+    {% endif %}
+    {% if item.transport_booked %}
+      <span class="badge text-bg-success">transport</span>
+    {% endif %}
+  </div>
+  <div class="grid-item">{{ item.topic }}</div>
+  <div class="grid-item">{{ item.location }}</div>
+  <div class="grid-item">
+    {% if country %}
+      {{ country.flag }} {{ country.name }}
+    {% elif item.online %}
+      💻 Online
+    {% else %}
+      <span class="text-bg-danger p-2">
+        country code <strong>{{ item.country }}</strong> not found
+      </span>
+    {% endif %}
+  </div>
+{% endmacro %}
+
+{% macro accommodation_row(item, badge) %}
+  {% set country = get_country(item.country) %}
+
+  {% set nights = (item.to.date() - item.from.date()).days %}
+  <div class="grid-item text-end">{{ item.from.strftime("%a, %d %b %Y") }}</div>
+  <div class="grid-item text-end">{{ item.to.strftime("%a, %d %b") }}</div>
+  <div class="grid-item text-end">{% if nights == 1 %}1 night{% else %}{{ nights }} nights{% endif %}</div>
+  <div class="grid-item">{{ item.operator }}</div>
+  <div class="grid-item">{{ item.location }}</div>
+  <div class="grid-item">
+    {% if country %}
+      {{ country.flag }} {{ country.name }}
+    {% else %}
+      <span class="text-bg-danger p-2">
+        country code <strong>{{ item.country }}</strong> not found
+      </span>
+    {% endif %}
+  </div>
+  <div class="grid-item">
+    {% if item.url %}
+      <a href="{{ item.url }}">{{ item.name }}</a>
+    {% else %}
+      {{ item.name }}
+    {% endif %}
+  </div>
+{% endmacro %}
+
+{% macro flight_row(item) %}
+  <div class="grid-item text-end">{{ item.depart.strftime("%a, %d %b %Y") }}</div>
+  <div class="grid-item">{{ item.from }} &rarr; {{ item.to }}</div>
+  <div class="grid-item">{{ item.depart.strftime("%H:%M") }}</div>
+  <div class="grid-item">
+    {% if item.arrive %}
+      {{ item.arrive.strftime("%H:%M") }}
+      {% if item.arrive.date() != item.depart.date() %}+1 day{% endif %}
+    {% endif %}
+  </div>
+  <div class="grid-item">{{ item.duration }}</div>
+  <div class="grid-item">{{ item.airline }}{{ item.flight_number }}</div>
+  <div class="grid-item">{{ item.booking_reference }}</div>
+{% endmacro %}
+
+{% macro train_row(item) %}
+  <div class="grid-item text-end">{{ item.depart.strftime("%a, %d %b %Y") }}</div>
+  <div class="grid-item">{{ item.from }} &rarr; {{ item.to }}</div>
+  <div class="grid-item">{{ item.depart.strftime("%H:%M") }}</div>
+  <div class="grid-item">
+    {% if item.arrive %}
+      {{ item.arrive.strftime("%H:%M") }}
+      {% if item.arrive.date() != item.depart.date() %}+1 day{% endif %}
+    {% endif %}
+  </div>
+  <div class="grid-item">{{ ((item.arrive - item.depart).total_seconds() // 60) | int }} mins</div>
+  <div class="grid-item">{{ item.operator }}</div>
+  <div class="grid-item">{{ item.booking_reference }}</div>
+{% endmacro %}